Front end tractor loaders and skid steer vehicles use bucket attachments for digging and loading materials and transporting the materials to a selected location. The vehicles have lift and tilt structures that control movements of the buckets and allow the buckets to be tilted forwardly to dump materials out of the bucket. C. M. Fisher in U.S. Pat. No. 3,598,266 and J. E. Zimmerman in U.S. Pat. No. 4,068,711 disclose buckets mounted on the lift arms of tractors for accommodating concrete and pouring concrete into a mold or a small area. The concrete in the buckets is not mixed in the buckets. Ready mix concrete or concrete from a concrete mixer must be placed in the buckets which are only used to transport and dump the concrete in selected locations. Concrete mixers have been developed to be mounted on tractors which transport mixed concrete to the work site. R. M. Bolt in U.S. Pat. No. 2,815,195 and F. Falardeau in U.S. Pat. No. 4,268,174 disclose concrete mixers having drum-type housings or buckets and concrete mixing blades and augers rotatably mounted on single shafts which are rotatably mounted on the end walls of the buckets. Two or more laterally spaced augers are not used to mix concrete in the bucket.